Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Beijing East Road, 71 Nanjing 210008, PR China; Joint Open Laboratory of Soil and the Environment, Hong Kong Baptist University and Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China.
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Beijing East Road, 71 Nanjing 210008, PR China.
Environ Pollut. 2018 Nov;242(Pt A):462-469. doi: 10.1016/j.envpol.2018.06.075. Epub 2018 Jul 6.
Laccases are capable of rapidly oxidizing benzo[a]pyrene. It is thought that the metabolites with an increase in water solubility caused by the oxidation of benzo[a]pyrene may stimulate the subsequent mineralization. However, to date, there has been no experimental evidence to support this. In this study, the fate of benzo[a]pyrene in soil affected by laccase amendment and the resulting soil bacterial responses were investigated. Laccase amendment promoted benzo[a]pyrene dissipation (15.6%) from soil, accompanied by trace mineralization (<0.58 ± 0.02%) and substantial bound residue formation (∼80%). An increase of ∼15% in the bound residue fraction was observed by laccase amendment, which mainly resulted from covalent binding of the residues to humin fraction. During the incubation, the abundance of bacterial 16S rRNA and polycyclic aromatic hydrocarbon ring-hydroxylating dioxygenase genes did not change markedly. In contrast, benzo[a]pyrene treated with laccase resulted in a smaller shift in the bacterial community composition, indicating a reduced disturbance to the soil microbial communities. These results here suggest that benzo[a]pyrene contaminated soil can be detoxified by laccase amendment mainly due to the enhanced bound residue formation to soil organic matter via covalent binding.
漆酶能够快速氧化苯并[a]芘。据认为，苯并[a]芘氧化导致的水溶性增加的代谢物可能会刺激随后的矿化。然而，迄今为止，还没有实验证据支持这一点。在这项研究中，研究了漆酶处理对土壤中苯并[a]芘的命运和由此产生的土壤细菌反应的影响。漆酶处理促进了土壤中苯并[a]芘的消散（15.6%），同时伴随着痕量矿化（<0.58±0.02%）和大量结合残留的形成（约 80%）。通过漆酶处理，观察到结合残留分数增加了约 15%，这主要是由于残留物与腐殖质分数的共价结合。在孵育过程中，细菌 16S rRNA 和多环芳烃环羟化双加氧酶基因的丰度没有明显变化。相比之下，用漆酶处理的苯并[a]芘导致细菌群落组成的变化较小，表明对土壤微生物群落的干扰减小。这些结果表明，苯并[a]芘污染土壤可以通过漆酶处理进行解毒，主要是由于通过共价键与土壤有机质形成增强的结合残留。
